Morphology of Poly(Ethylene Oxide)b-Poly(epsilon-Caprolactone) Spherulites Formed Under Compressed CO2

Melt crystallization of PEO-b-PCL thin films was conducted under compressed CO2 and the morphology of the spherulites obtained at various pressures was investigated by polarizing optical microscopy (POM) and atomic force microscopy (AFM). At 3 MPa CO2 classical ring-banded spherulites with periodical twisting lamellae formed. However, in the spherulites with concentric ring-banded structures formed at 5 MPa CO2, the rings were formed due to periodical variations in thickness along the radial direction